This invention relates to communications and, more particularly, to communications over a plurality of channels.
Multimedia, as the name implies, comprises information that is intended for different presentations. This includes, for example, video and audio, video and data, etc. Often, multimedia arrangements employ different channels in a communication network for communicating the different information portions that belong to the different media. Those different channels can have different transfer characteristics, such as delay, attenuation, digital rate conversion, etc. There are even applications where the communication network simply discards information or creates segments of replicated information.
In situations as described above, where different channels are used for communicating multimedia information signals, there is a potential danger that the receiving end will receive the information from the different channels in a temporal relationship to each other that is different from the temporal relationship of the sent information. This, of course, can become quite objectionable to users. For example, when the video image of a speaking person is not synchronized with the voice of the utterances spoken, the users' perception is that the transmission and/or the source are flawed.
What is needed, therefore, is a method for measuring the temporal relationship between different channels so that appropriate channels are selected, or so that the channels can be modified to produce an improved state of temporal synchronization.